Ultrasound imaging is a medical imaging technique for imaging organs and soft tissues in a human body. Ultrasound imaging uses real time, non-invasive high frequency sound waves to produce a two-dimensional (2D) image and/or a three-dimensional (3D) image.
Ultrasound imaging may be helpful in evaluating the progression of labor and/or other fetal measurements by allowing examination of cervical dilation, fetal presentation, position, and descent. A prolonged second stage of labor is a type of dystocia, whereby the fetus has not been delivered within three hours in nulliparous women or two hours in multiparous women, after the cervix has become fully dilated. Women undergoing a prolonged second stage of labor typically need intervention, which involves instrumental delivery (using obstetric forceps or ventouse) or Cesarean section or failed instrumental delivery followed by Cesarean section.
In recent years, the rate of Cesarean section has increased dramatically. The failure to progress and fetal distress are the two most common indications for performing surgical deliveries or Cesarean section. Cesarean sections are associated with the risk of maternal morbidities such as bladder trauma and hematoma and unnecessary Cesarean sections are best avoided.
Currently, digital examination of fetal descent using transvaginal imaging is considered the ‘gold standard’ for evaluating fetal head station, but this method is subjective and inaccurate with high interobserver variability. Recent studies have shown that transperineal ultrasound imaging might allow objective quantification of the level of fetal head descent in the birth canal. Multiple measurements have been proposed including the fetal head-perineum distance and measuring the ‘angle of progression’ (AOP) to evaluate the labor progress. With regard to AOP, it has been shown that the greater the AOP in the second stage of labor, the greater the probability of successful assisted or spontaneous delivery. Studies with fetuses in the direct occipitoanterior position have shown that the AOP correlates well with the decision to opt for spontaneous vaginal or instrumental delivery or Cesarean section. There is growing evidence suggesting that, AOP may constitute a suitable, objective tool to evaluate progress of labor.
Earlier efforts at improving robustness and accuracy of clinical workflow in the labor room combine position tracking technology with advanced ultrasound imaging to objectively determine fetal head station. For example, LABORPRO, which was developed by TRIG MEDICAL, maps the maternal pelvis by manually marking points on the pelvis or using a position sensor. This is followed by marking known fetal head landmarks on the ultrasound image. The two markings enable LABORPRO to determine the spatial position of the fetal head in relation to the pelvic bone. However, the system in LABORPRO does not work fully automatically and requires manual interaction. Existing systems also do not display labor progress or other fetal measurement information in a manner suitable for understandability by non-medical persons.
Further limitations and disadvantages of conventional and traditional approaches will become apparent to one of skill in the art, through comparison of such systems with some aspects of the present invention as set forth in the remainder of the present application with reference to the drawings.